Electron tube



June 30, 1936. G. JOBST ET AL.

ELECTRON TUBE Filed Oct. 28, 1955 V B D I I I o D D n O 0b tubes required for the receiver.

Patented June 30, 1936 UNITED. STATE-S PATENT ()FFICE ELECTRON TUBE Gunther 'Jobst and Horst Bethe, Berlin, Ger- -many, 'assignors to Telefunken Gesellschaft fiir Drahtlose Telegraphic m. b. '11., Berlin, Germany, a corporation of .Germany 9 Claims.

Various constructions of multi-tubes are already knownwith which it is aimed .on the one hand at saving space in the receiver and on the other hand at decreasing the cost ,of the set of In general such multietubes are. so constructed that individual or separate electrcdejjsystems are arranged side by side within" the glassbulb. Often a common cathode is used tor all the systems, and since the various electrode systems are arranged alongside the cathode; the latter has a correspondingly great length. Such tube is shown schematically According to the present invention individual or separate electrode systems are not placed adjacent to eachother along the cathode, but instead the electrodes, preferably of about the length of the entire system, are'arranged behind each other and certain'pa'rts of said electrodes are constructed differently in the direction of the cathode in regard to spacial dimensioning, shaping, and permeability'to current. The grid electrodes are of particular concern in this respect, the diameter of which and thespacing of its turns being capable of variations within wide limits. Also the provision of inactive places in the electrode surfaces and the covering of only a portion of the cathode length by some electrodes are .to be considered modifications in the shapegof the electrode systems in the direction of the cathode; In this manner it ispossible'to arrange difierent electrode combinations opposite various partsof' the'cathode so that the electron current leaving-the cathode will be divided into separate-current paths, controlled in various'manner; In accordance as to whether a possibly independent-control, or a certain relation pn which these paths depend, is intended, the

variation intheshaping of the electrodes can be made within sudden steps and within extreme differences or a gradual zone can be provided therebetween. Further possible embodiments the opposite direction. It is further conceivable that the conditions in the through grip within the sectionsof the electrode system continuously varies, which sections result from the various shaping of single electrodes and that such condition may serve to cause the characteristic of the respective current path to take a course difierent from that obtained in accordance with the Est 3/ 2-law (Est=control voltage).

In the type of tubes hitherto known in which in the direction of the cathode a different shaping'of electrodes was: provided, such measure was resorted to in a different manner as well as for other purposes, for instance in order to obtain a logarithmic course of the characteristic, or to compensate the voltage drop along the filament {of directly heated incandescent cathodes and to produce a homogeneous field distribution. In the present case however, on the contrary,' it

is aimed at a non-homogeneous control action rent paths independently influenced to different extents by the individual electrodes.

Figure 2 shows an embodiment, by way of ex- V ample of such a tube having the same properties as the double tube shown in Figure 1.

In the left half the grid G1 surrounding the cathode C is closely wound whereas at the right the turns are very grid bars are without turns, so that on this side the flow of the electron current is not or only to a small extent influenced by the electrode.

" The succeeding grid G2 is common to both halves although'acting on the left side as screen grid and on the right side as space charge grid, and

' itis uniformly constructed over the entirel'ength or the system. In the left half the electrode Go in front of the plate P has a very large grid winding pitch whereas in the right half the pitch is small. In this case the left part of the electrode has no notable controlling action. As regards electrical effects the tubes according to Figures 1 and 2 are not distinct from each other and at the formation of adjacent electron cur- Particu- -lar emphasis is laid on the extreme differences in the pitch of the grid turns.

'far apart, denoting in the extreme case that the yet it will be noted from Figure 2 that the electrode system in this figure can be mounted in the same simple manner as that of any single tube.

Figure 3 is intended to elucidate the practical mounting showing the one side support of the electrodes, which are denoted by the same reference characters employed in Figure 2.

Figure 4 presents a further example of the use of a multi-tube operated in accordance with the features of the present invention. In this case also two current paths are controlled but in an entirely different manner from Fig. 2. The left half of the tube operates as high-frequency amplifier; the first grid G01 is the control electrode; the second grid G02 on this side remains ineffective due to the grid bars being without windings, and the third grid Gp serving as anode for this circuit is so closely wound that the electrode disposed in back thereof has no appreciable through grip. The right half of the tube represents a back coupled audion, the first and third grids G81 and G being inactive while the second grid G02 serves as the control grid. In operation the circuit functions in the following manner: The tunable grid circuit Aa, connected between cathode C and grid Gel through the biasing battery B, is tuned to the frequency of the signal to be received. The amplified signal oscillations appear in the output circuit C, S, T1, G C. The tunable grid circuit Ad, connected between the cathode C and the grid Gc2 through the grid leakcondenser combination K, is also tuned to the signal frequency and is coupled to the amplifier output circuit through transformer T1T2. The detector output circuit C, S, T, T3, P, C is regeneratively coupled to the tuned grid circuit Ad by means of the windings T3, T2, the detected signal being indicated in the telephone T.

A further example of a circuit is shown in Figure 5 explaining the use of twin-tubes in a sound transmitter for two frequencies on and ea. In the left half or the tube the first grid G1 serves for exciting the frequency wz, while in the right half the other frequency or is back coupled to the third grid G3; the second grid G2 is common to both halves and acts as a screen grid and a space-charge grid, respectively. It will be readily seen that such a tube can be employed with particular advantage as a mixer tube in intermediate frequency receivers.

What we claim is:-

1. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of grid electrodes interposed between cathode and anode, the grid electrode nearest the anode being divided along the length of the cathode into distinct portions, each of uniform grid openings, but the grid openings of the various portions being different said grid portions and corresponding portions of the other grid electrodes cooperating with the cathode and anode to perform different functions.

2. A multi-function electron discharge tube comprising a cathode, an anode and a plurality V of helically wound grid electrodes interposed between cathode and anode, the grid electrode nearest the anode being divided along the length of the cathode into distinct portions, each of uniform pitch, but the pitches of the various portions being different, said grid portions and corresponding portions of the other grid electrodes cooperating with the cathode and anode to perform different functions.

3. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of helically wound grid electrodes interposed between and coextensive with said cathode and anode and surrounding the cathode, the grid electrode nearest the anode being provided with 5 widely spaced but uniform turns for substantially one-half of its length and with closely spaced but uniform turns for substantially the other half of its length, said half-length grid sections and corresponding sections of the other grid electrodes cooperating with the cathode and anode to perform different functions.

4. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of helically wound grid electrodes interposed between and coextensive with said cathode and anode and surrounding the cathode, the grid electrode nearest the anode being provided with widely spaced but uniform turns for substantially one-half of its length and with closely spaced but uniform turns for substantially the other half of its length, the next adjacent grid electrode being provided with uniformly spaced turns throughout its length, said half-length grid sections and corresponding sections of the other grid electrodes cooperating with the cathode and anode to perform different functions.

5. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of helically wound grid electrodes interposed between and coextensive with said cathode and anode and surrounding the cathode, one of said grid electrodes being provided with widely spaced but uniform turns for substantially one-half of its length and with closely spaced but uniform turns for substantially the other half of its length, and a second grid electrode being provided opposite the widely spaced turns of the first mentioned grid electrode with closely spaced but uniform turns and being provided for substantially the other half of its length with widely spaced but uniform turns.

6. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of helically wound grid electrodes interposed between and coextensive with said cathode and anode and surrounding the cathode, the grid electrode nearest the cathode being provided with widely spaced but uniform turns for substantially one-half of its length and with closely spaced but 50 uniform turns for substantially the other half of its length, the next adjacent grid electrode being provided opposite the widely spaced turns of thegrid electrode. nearest the cathode with closely spaced but uniform turns and being proyided for substantially the other half of its length with widely spaced but uniform turns.

'1. A multi-function electron discharge tube comprising a cathode, an anode and a plurality of helically wound grid electrodes interposed between and coextensive with said cathode and anode and surrounding the cathode, the grid electrode nearest the cathode being provided with widely spaced but uniform turns for substantially one-half of its length and with closely spaced but uniform turns for substantially the other half of its length, the next adjacent grid electrode being provided with uniformly spaced turns throughout its length and the third grid electrode being provided opposite the widely spaced 7 turns of the grid electrode nearest the cathode with closely spaced but uniform turns and being provided for substantially the other half of its length with widely spaced but uniform turns.

8. A multi-function electron discharge tube comprising a cathode and an anode, a plurality of grid electrodes interposed in the space between said cathode and anode, independent support rods for each of said grid electrodes, and the grid electrode nearest the anode and that adjacent the cathode, each being provided with widely spaced but uniform turns for substantially one half of its length and with closely spaced but uniform turns for substantially the other half of its length, the grid turns of each electrode being mounted on a common support rod for electrical connection to the same potential source.

9. A multi-functlon electron discharge tube comprising a cathode and an anode, first, second and third grids interposed in the space between said cathode and anode, the first grid elec trode being provided with widely spaced but uniform turns for substantially one half of its length and with closely spaced but uniform turns for substantially the other half of its length, the second grid being provided with uniformly spaced turns, the third grid being provided opposite the widely spaced turns of the first grid with closely spaced but uniform turns and provided opposite the closely spaced turns of the first grid with widely spaced turns, and independent support rods for each of said grids.

GUNTHER JOBST. HORST ROTHE. 

